Optimization Research Of Formula For Stabilizing Lacustrine Soft Soil In Hefei

Lacustrine soft soil layers are broadly distributed in Binhu New District,Hehei,with muddy clay as the dominant component and high water content,low bearing capacity and large settlement deformation as characteristics,which is harmful to urban construction in Binhu New District.Currently,the curing agent dominated by cement is mainly applied to projects for soft soil improvement,resulting in relatively unsatisfactory actual effects with high costs and environment pollution.Thus,a number of scholars have conducted researches on formula of compound curing agent.In this paper,Ca O and soda are added to GGBS(Ground granulated blastfurnace slag)as activators and are used to stabilize lacustrine soft soil in Hefei.The change rules of strength of the stabilized soils were carried out using unconfined compressive strength tests.The optimizating mixture ratio of GGBS,Ca O and soda were obtained from Box-Behnken method,with the contents of GGBS,Ca O and soda ash as affecting factors,with the unconfined compressive strength values of 7 day and 28 day as response values.Box-Behnken method is an experimental design method which is capable of simultaneously considering multiple influencing factors to achieve the optimum targeted value.It has been widely applied to technical formula design in aspects like cereals,soils,foodstuffs,chemical industries and biological engineering.It can not only establish the functional relationship between influencing factors and targeted values,but also analyze the interaction law among different influencing factors.In this research,Box-Behnken method is firstly applied to development of solidifying formula of lacustrine soft soil in Hefei.The result shows that strength as response value are much influenced by the change of GGBS content and becomes more sensitive to the content of GGBS as the age increases.However,the situation is reverse for Ca O and soda ash.With the age of7 days,the contents of three additives have linear effect and surface effect on response values and the mutual-influence for Ca O and soda is significant.With the age of 28 days,the mutual-influence for GGBS and soda is significant.By mutual-influence analysis,it is found that the optimal ratios of GGBS content,Ca O content,soda content are 13.08%,4.89% and 1.25% respectively.Under the the optimal ratios ofthree additives,the prediction strength of stabilized soils can reach 550.904 k Pa after 7days and 665.953 k Pa after 28 days.Finally,the actual strength values are compared with the prediction strength values.The results provide theoretical reference for GGBS stabilizing soft soil of the lakeside new distract in Hefei.